We often personify trees and are always impressed by their long lives it’s no wonder folk memory often includes stories of individual trees.
The phrase ‘Knock on Wood’ has several argumentative origins. A common explanation traces back to Pagan cultures such as the Celts. The Celts believed spirits and Gods resides in the trees. Knocking on wood could possibly serve as a way to rouse the spirits to ask for protection or to show gratitude for a streak of good luck.
Dan Dennett Philosopher, cognitive scientist who argues that human consciousness and free will are the result of physical processes.
George David Haskell The Songs of Trees.
Suzanne Simard’s Ted Talk“How Trees Talk to Each Other.”
Suzanne Simard’s story and thesis summary :Exploring How and Why Trees 'Talk' to Each Other
A bunch of Nation Geographic Articles that helped us out: